| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a malfunction caused by an analog signal from occurring by converting an analog detecting signal of a sensor into a digital signal by means of an A/D converter and outputting it to a controller. SOLUTION: A sensor 11 for detecting temp. or pressure of a molten resin in a joint is fitted on an electrofusion joint wherein an electric wire is embedded in a coil-like shape or spirally on a bonding face with a plastic pipe and a switch means for controlling to start and to end energization of electricity to the electrofusion joint is controlled by a controller 13. After electricity is energized, the switch means is made OFF based on the detected value of the sensor 11 by the controller 13 to end energization of electricity. In this case, an analog detecting signal of the temp. sensor 11 is converted to a digital signal by means of an A/D converter 12 and it is outputted to the controller 13. In addition, a signal wiring 14 and a power wiring 15 from the A/D converter 12 to the controller 13 are put in the same cable 16.</p> |
